#include "mystdio.h"


#include<string.h>
#include<stdlib.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<fcntl.h>
#include<unistd.h>



mFILE* mfopen(const char* filename,const char* mode)
{
    int fd = -1;
    if(strcmp(mode,"r")==0)
    {
        fd = open(filename,O_RDONLY);
    }
    else if(strcmp(mode,"w")==0)
    {
        fd = open(filename,O_CREAT | O_WRONLY | O_TRUNC,0666);
    }
    else if(strcmp(mode,"a")==0)
    {
        fd = open(filename,O_CREAT | O_WRONLY | O_APPEND,0666);
    }

    if(fd < 0 )
        return NULL;

    mFILE* mf = (mFILE*)malloc(sizeof(mFILE));
    if(!mf)
    {
        close(fd);
        return NULL;
    }
    
    mf->fileno = fd;
    mf->flag = FLUSH_LINE;
    mf->size = 0;
    mf->cap = SIZE;

    return mf; 
}


void mfflush(mFILE* stream)
{
    if(stream->size > 0)
    {
        write(stream->fileno, stream->outbuffer, stream->size);
        // 刷新到外设
        fsync(stream->fileno);
        stream->size = 0;
    }
}


int mfwrite(const void *ptr, int num, mFILE *stream)
{
    // 1. 拷贝
    memcpy(stream->outbuffer+stream->size, ptr, num);
    stream->size += num;

    // 2. 检测是否要刷新
    if(stream->flag == FLUSH_LINE && stream->size > 0 && stream->outbuffer[stream->size-1]== '\n')
    {
        mfflush(stream);
    }
    return num;
}


void mfclose(mFILE *stream)
{
    if(stream->size > 0)
    {
        mfflush(stream);
    }
    close(stream->fileno);
}
